Thanks for the tip I’ll look into a few of the options out there but I do like the idea of having the “old school knowledge” in my back pocket. The Serial number is 7321, so a late December ‘39. Terrie sent me the original build info pdf and the machine was ordered to Harrison Radiator Division, General Motors Co. in Lockport New York. The pallet it was on when I bought it had a tag from a casting company in P.A. I’m in Cleveland Ohio so it seems this machine as been out near me the whole time. It now resides in my home shop where I work on old motorcycles.
The "guts" of Stewart-Warner mechanical tachos & speedometers covered "many" layouts and even diameters of display dials and needles. In PM's annals there HAVE been some stories about these being rebuilt by speedometer repair shops. Which type of shops must, by now, be few and far between, largely serving the "classic" restored auto and cycle markets, and charging accordingly.
I just snatched-up several "NOS" Stewart-Warner "Marine / Diesel" tachometers, complete - because they already had a useful RPM range for my MG-era "round dial" 10EE's.. whereas a 6,000 or 8,000 RPM automotive, or a 12,000 or so motorcycle tacho isn't even close.
On my 1942 the OEM tach works fine. The 1944 is in need, and I have acquired an OEM tach in used condition, untested, out of another round-dial part-out.
Can these newer ones be adapted as replacements?
"Probably" but not trivially.
Arse end:
Faces:
Note depth and drive input differences that might require a tube to position the tacho protruding from the surface of the HS so the clamp and drive end could be adapted.
OTOH, these are not the only possible donors, the goods are cheap, and if done with care, an original tach could be put in when you find one LATER.
I am NOT married to the original location, however.
I'd PREFER a tacho in a "bullet pod" (common auto accessory..) and on a stalk so the head can be swiveled and aimed directly at the operator's eyeshot. My speed controls go on the apron, not the body of the lathe. Why have to move?
That gets easier if an electrical (analog tacho-generator sender) or electronic (digital/pulse sender) is used instead of mechanical.
So I have several types of these in the "Hell box" , S-W & European.
Note the DIP switch rather than a socket for a mechanical shaft.
NB: The "collection" because I have two mills and one other lathe (Cazeneuve) to put tachos onto as well.
One mill already has a mechanical output 'coz a tach was a factory option.
Even so, I may go electronic off Hall-effect, mag-prox, or optical sender.
It's just cheaper, easier, better, and has all manner of "appearance" choices, what with the massive vehicle market.
All "futures" stuff, no pressing need, and too much else on my plate already, so "don't wait on ME!" .. to tell or show the way!
